Puffins return to their breeding colonies in March and April, and to prepare for this they gather in tightly-packed 'rafts' offshore. Here the pairs display to each other, rubbing bills and cooing, before mating and coming ashore to the grassy slopes of their breeding ground. By now, their beaks have become brightly coloured and they have developed a whiter face with a horny blue patch above and below the eye.
A puffin colony sometimes has several thousand pairs. The birds usually pair for life, though they are not necessarily together all year round. The puffins may dig a shallow burrow, about 2 metres long, in the soft turf on cliff tops and islands, or use an old rabbit burrow. They return to the same burrow every year. On land, the pairs strengthen their bond by preening each other and tossing their heads. The males often present the females with gifts of grass or feathers.
A single egg is laid in a chamber at the end of the burrow and both parents take turns to incubate it which take 39 days. The newly hatched chick (or puffling) is covered in dark brown down and has a small black bill. Its parents share the task of feeding it, flying out to sea to catch beakfuls of sand eels. After about 40 days, the chick is deserted and stays in it burrow for 7 - 10 days, without food, whilst its adult feathers develop.
Leaving the burrow is a dangerous time for the young puffin, so it emerges at night to avoid hungry gulls. It cannot yet fly, so it tumbles down the cliff face and swims as far out to sea as possible before daybreak. It then starts learning to fly and fish. The following year, the young puffin returns to the colony, although it does not breed until it is four or five years old.
Off the United Kingdom, there are large puffin colonies in the Outer Hebrides in the north of Scotland, Skomer Island in Pembrokeshire, Bempton on Humberside and Portland Bill in Dorset.Read More: Puffin Habits